Force Sensing Touchscreen
A touchscreen that determines the point of touch and magnitude of a force applied to the touchscreen is disclosed. The force can be perpendicular, parallel, or sloped with respect to the touchscreen surface. The force can also be a plurality of forces simultaneously applied to the touchscreen surface where the centroid and resultant of the plurality of forces are determined. The touchscreen can take the form of various two-dimensional or three-dimensional shapes such as a circle, cube, sphere, cylinder, or the like.
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This application is a continuation-in-part of a U.S. patent application Ser. No. 12/587,339, filed Oct. 6, 2009, titled “Touch Sensing Technology”.
BACKGROUNDDifferent technologies are used in touchscreens, including capacitive, resistive, infrared, and acoustic wave. While some of these technologies can sense the position of touch between a touching panel and an object touching the touching panel, they cannot always sense the magnitude of the force applied by the object to the touching panel at the moment of touch. Sensing the magnitude of the force can be utilized in various computer applications. For example, it can be used to provide the computer system with an immediate input representing a speed of movement in a gaming application, a depth of a third dimension in a 3D application, a size or color transparency of an object in a graphics application, or the like.
There are a number of US patents and patent applications that disclose the use of force sensing in touchscreens to determine the magnitude of a pressure or force applied against a touchscreen. For example, the U.S. Pat. No. 7,196,694 of 3M INNOVATIVE PROPERTIES COMPANY discloses a device for determining the position and magnitude of a force applied to a touch screen. The device includes a plurality of beam members or strips, each of which is connected, from its bottom side, to two supports with one or more force sensors. When a force is applied to the top of the beam member, the force passes to the two supports and is detected by the one or more force sensors.
The U.S. patent application Ser. No. 12/939,078 of QUALCOMM INCORPORATED proposes using a plurality of force sensors around the bottom perimeter of a touching panel. When a force is applied to the top side of the touching panel, the force passes to the bottom perimeter of the touching panel to be detected by the force sensors. Also, the U.S. patent application Ser. No. 12/725,699 of MOTOROLA INCORPORATION suggests using a combination of two layers of surfaces located on top of each other. The first layer is a touchscreen surface to detect the position of touch, and the second layer is a force sensing surface to detect the magnitude of the force applied at the position of touch. The two layers or surfaces combined provide the computer system with an immediate input representing the point of touch and the magnitude of the force applied to the touchscreen.
However, there are several disadvantages related to the design and method of how the force sensors are utilized in the touchscreens of the aforementioned issued patent and patent applications. The first disadvantage is that the force sensors can only detect the perpendicular force applied to the touchscreen in one direction. For example, if the touchscreen is positioned on a flat surface parallel to the xy-plan, the user can apply a force in the negative z-axis to the touchscreen, but cannot apply a force in the positive z-axis. Accordingly, it is possible to gradually increase the force applied to the touchscreen, but it is impossible to gradually decrease the force applied to the touchscreen when the touchscreen is initial touched.
The second disadvantage in the aforementioned cases, is that the force sensors cannot detect the force applied parallel to the touchscreen. This is limiting, as a parallel force applied to the touchscreen surface could be of considerable importance in many computer applications, in comparison to the perpendicular force acted on the touchscreen. For example, it is easy to apply two parallel forces to the touchscreen, where the two parallel forces are in two opposite directions relative to each other. The two opposite and parallel forces to the touchscreen can be along the negative x-axis and the positive x-axis; or along the negative y-axis and the positive y-axis of the touchscreen plane. Parallel force applied to the touchscreen can follow various directions in the xy-plane to represent different inputs. For example, the parallel forces can be aligned to zero and 180 degrees, 90 and 270 degrees, 45 and 225 degrees, or 135 and 325 degrees to represent increasing or decreasing four different inputs. These four results can be achieved without changing the point of touch of the finger on the touchscreen, opposite to the perpendicular force which is incapable of achieving this function.
The third disadvantage of using the force sensing mechanism of the aforementioned issued patent and patent applications, is the inaccuracy of determining the force magnitude when the force is applied in a downward 3D-diagonal direction relative to the touchscreen surface. This is based on a model which structurally represents the force by a first force parallel to the touchscreen surface, and a second force perpendicular to the touchscreen surface. The first force is then neglected where it cannot be sensed by the force sensors, while the second force is sensed by the force sensors. In this case, the value of the second force is always less than the value of the original force. This confuses the user when s/he applies more force with his/her finger to the touchscreen without seeing any effect in his/her input displayed by the computer display, especially when the tilted direction of the finger is closer to the touchscreen plane.
The fourth disadvantage is related to the deficiency of each one of the above mentioned patent and patent applications. For example, the technique of the U.S. Pat. No. 7,196,694 of 3M INNOVATIVE PROPERTIES COMPANY divides the touchscreen into a plurality of strips in the form of beam members which complicates the design and the manufacturing of the touchscreen. The U.S. patent application Ser. No. 12/939,078 of QUALCOMM INCORPORATED uses a large number of force sensors which increases the cost of the touchscreen especially bigger sized touchscreens. The U.S. patent application Ser. No. 12/725,699 of MOTOROLA INCORPORATION utilizes two layers or surfaces on top of the computer display which affects the clarity of the digital data presented on the computer display, in addition to, increasing the cost of the touchscreen.
There is a need for a new technology for touchscreens that detects the forces applied to the touchscreen whether this force is perpendicular, parallel, or sloped relative to the touchscreen surface. This technology should be simple and utilize a minimum number of force sensors thus lowering costs, and also increasing the clarity of the digital data presented on the computer display.
SUMMARYIn one embodiment, the present invention discloses a force sensing touchscreen that detects both of the position of touch and the magnitude of the force applied to the touchscreen regardless of the direction of the force relative to the touchscreen surface. For example, the present invention determines the perpendicular force in relation to the touchscreen surface, whether this force is along the positive or negative z-axis. This is not the case with the prior art of touchscreens which only detect the perpendicular force along the negative z-axis. Also, the present invention detects the parallel force to the touchscreen surface, where this parallel force cannot be detected by any of the prior art technologies. Moreover, the present invention detects the accurate magnitude of the sloped force on the touchscreen surface, which is a unique feature relative to other available technologies that cannot detect the accurate magnitude of the sloped force.
In another embodiment, the present invention determines the resultant and the centroid of multiple forces simultaneously applied to a touchscreen. The multiple forces can be in different three-dimensional directions relative to the touchscreen surface, and also relative to each other. For example, some of the multiple forces can be perpendicular to the touchscreen surface, and others can be parallel to the touchscreen surface, while one or more of the multiple forces can be sloped relative to the touchscreen surface. In this case, the centroid of the multiple forces is represented by a point located on the touchscreen, while the resultant of the multiple forces is represented by a magnitude along a three-dimensional direction.
Overall, the design of the present invention is straightforward, and the number of the force sensors utilized in the touchscreen is minimum, which simplifies the manufacturing process and reduces the cost of the present invention. Additionally, the present invention of force sensing touchscreen can take different two-dimensional shapes such as a rectangle, triangle, circle, or the like. It can also take the form of various three-dimensional shapes such as a cube, sphere, cylinder, pyramid, or the like. Adding variation to shapes of touchscreens opens the door for new software applications and utilization of touchscreen technologies. Also, the force sensors utilized in the present invention have no impact on the clarity of the digital data presented on the computer display, allowing the user a crisp visual experience.
Generally, the above Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
To clarify the concept of the present invention,
The value of the vertical force can be computed by adding the four values of the four forces or reactions that are exerted at the positions of the four force sensors, whereas these four reactions represented by the output of the four force sensors. The position of the touch point can be computed by solving the equilibrium equations of the vertical force and the four reactions of the four force sensors as will be described subsequently. When the vertical force is moved on the touch surface the successive positions of the points of touch can be computed to represent the path of the vertical force movement on the touch surface. The vertical force can be any object that has a weight or applies a pressure such as a user's finger, a pen, or the like.
Overall, the concept of utilizing the force sensors can be implemented in various computer input devices. For example,
The present touchpad has many advantages in comparison to the traditional touchpad. For example, the magnitude of the vertical force can be utilized to represent the speed of moving objects on the computer display without utilizing additional buttons or using another finger. Moreover, in case of adding four force sensors to the boundary sides of the rectangular touch surface, as described previously, then the touchpad can detect the 3D direction of the exerted force which can be utilized to manipulate the objects to move in 3D on the computer display.
The idea of using the force sensors can be implemented in various 3D computer input devices that enable the user to manipulate the objects to move in 3D on the computer display. For example,
Overall, the main advantage of the present invention is utilizing an existing hardware technology that is simple and straightforward which easily and inexpensively carry out the present touch sensing touchscreen. For example, the force sensor can be a digital force sensor or an analog force sensor that detects the exerted force on its surface and generates a signal representing the value of this force. The two commercially available force sensors in the market are in the form of a push button and a fixable strip where both of them can be easily utilized with the present invention. The microprocessor receives the signal of the force sensors and provides the computer system with an immediate input representing a movement in two or three-dimensions on the computer display.
The algorithm of the present touch sensing technology depends on structurally analyzing the output of the force sensors to compute the position, the magnitude, and/or the direction of the force that is exerted form an object on the touch surface. Generally, as described previously the elements of the present touch sensing touchscreen has three different structural forms. The first structural form is illustrated in
According to the structure analysis of the elements of
Fv=R1+R2+R3+R4
y=(0.5 W−(LR2+WR4+(L2+W2)·0.5R3)2/2WFv2)+(WR1+LR3+((L2+W2)0.5R2)2/2WFv2
x=(((WR1+LR3+(L2+W2)0.5R2)2/Fv2)−y2)0.5
In the previous equations, “Fv” represents the value of the vertical force. R1 represents the reaction of the first force sensor that is located on the upper left corner, R2 represents the reaction of the second force sensor that is located on the upper right corner, R3 represents the reaction of the third force sensor that is located on the lower right corner, and R4 represents the reaction of the fourth force sensor that is located on the lower left corner of the touch surface. “x” and “y”, respectively, represent the horizontal distance and the vertical distance of the vertical force relative to the left bottom corner of the touch surface. “L” represents the length of the touch surface, and “W” represents the width of the touch surface.
According to the structure analysis of the elements of
tan θ=R1/R2 and Fh=R1/sin θ
If the direction of the horizontal force is located between the first force sensor and the fourth force sensor then;
tan (θ−90)=R4/R1 and Fh=R4/sin (θ−90)
If the direction of the horizontal force is located between the third force sensor and the fourth force sensor then;
tan (θ−180)=R3/R4 and Fh=R3/sin (θ−180)
If the direction of the horizontal force is located between the second force sensor and the third force sensor then;
tan (θ−270)=R2/R3 and Fh=R2/sin (θ−270)
In the previous equations, “Fh” represents the value of the horizontal force. R1, R2, R3, and R4 represent the four reactions of the four force sensors that are, respectively, located at the top side, right side, bottom side, and left side of the touch surface, while 0 represents the angle between the horizontal force and the positive of the x-axis.
According to the structure analysis of the elements of
tan φ=Fv/Fh
F=Fv/sin φ
It is important to note that in case of using the portable touch screen of
It is also important to note that the touchpad of
In another embodiment, the present invention determines the centroid and resultant of a plurality of forces simultaneously applied to a surface. For example,
Determining the centroid and resultant of a plurality of forces simultaneously applied to a surface can be utilized in various computer applications. For example, in a gaming application, touching the touchscreen with a hand while applying forces by the hand to the touchscreen in a 3D direction provides the computer system with an input representing a movement of an object in the same 3D direction on the computer display. In this case, the centroid of the forces of the hand represents the point of touching the object on the computer display, and the resultant of the forces represents the pressure of pushing the object to move in the 3D direction on the computer display.
Generally, the concept of positioning a force sensor at each corner of the touchscreen surface can be utilized in creating various innovative shapes of touchscreens. For example,
The square frame can be used with a variety of shapes such as circles, pentagons, hexagons, or octagons to reduce the number of sensors to four sensors positioned at the four corners of the square frame. The triangular frame can also be used in place of the square frame to reduce the number of the sensors needed to three sensors positioned at the three corners of the triangular frame. Utilizing a frame to support the touchscreen can be used to create touchscreens with more complicated shapes. For example,
Overall, as discussed above, a force sensing touchscreen is disclosed, while a number of exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.
Claims
1. A touchscreen to detect the position of touch and the magnitude of a force applied to a touching panel wherein the force can be parallel, perpendicular, or sloped to the touching panel, and the touchscreen is comprised of;
- a touching panel comprised of multiple surfaces attached to each other in three-dimensions;
- a plurality of sensors each of which is positioned at a corner of a surface of the multiple surfaces to detect the partial force applied to the corner;
- a microprocessor that receives the data of the partial forces from the plurality of sensors and determines the position of touch and the magnitude of the force.
2. The touchscreen of claim 1 wherein the touching panel has two faces and side edges and the force is applied to one of the two faces.
3. The touchscreen of claim 1 wherein each surface of the multiple surfaces is a flat surface and the multiple surfaces are attached to each other to form a three-dimensional shape.
4. The touchscreen of claim 1 wherein one or more surfaces of the multiple surfaces are curved surfaces and the multiple surfaces are attached to each other to form a three-dimensional shape.
5. The touchscreen of claim 1 wherein the plurality of sensors are force sensors.
6. The touchscreen of claim 1 wherein each sensor of the plurality of sensors detects the movement of a corresponding surface of the multiple surfaces due to the force.
7. The touchscreen of claim 1 wherein the force is multiple forces simultaneously applying to the touching panel, and the positions of touch and the magnitudes of the multiple forces are determined.
8. The touchscreen of claim 1 further the plurality of sensors are positioned at the corners of a wireframe attached to the touching panel.
9. A touchscreen to detect the centroid and resultant of multiple forces simultaneously applying to a touching panel at different positions wherein each force of the multiple forces can be parallel, perpendicular, or sloped to the touching panel, and the touchscreen is comprised of
- a touching panel comprised of multiple surfaces attached to each other in three-dimensions;
- a plurality of sensors each of which is positioned at a corner of a surface of the multiple surfaces to detect the partial force applied to the corner;
- a microprocessor that receives the data of the partial forces from the plurality of sensors and determines the centroid and resultant of the multiple forces.
10. The touchscreen of claim 9 wherein the centroid is represented by a location on the touching panel, and the resultant is represented by a magnitude along a three-dimensional direction.
11. The touchscreen of claim 9 wherein the touching panel has two faces and side edges and the multiple forces are applied to one of the two faces.
12. The touchscreen of claim 9 wherein each surface of the multiple surfaces is a flat surface and the multiple surfaces are attached to each other to form a three-dimensional shape, and the multiple forces are applied to one or more of the multiple surfaces.
13. The touchscreen of claim 9 wherein one or more surfaces of the multiple surfaces are curved surfaces and the multiple surfaces are attached to each other to form a three-dimensional shape, and the multiple forces are applied to one or more of the multiple surfaces.
14. The touchscreen of claim 9 wherein the plurality of sensors are force sensors.
15. The touchscreen of claim 9 wherein each sensor of the plurality of sensors detects the movement of a corresponding surface of the multiple surfaces due to the multiple forces.
16. A method for determining the position of touch and magnitude of a force applied to a plurality of surfaces attached to each other at the edges in three-dimensions wherein the method comprising;
- detecting the partial force at each corner of each surface of the plurality of surfaces due to the force; and
- analyzing the partial forces at all corners of all surfaces of the plurality of surfaces to determine the position of touch and magnitude of the force.
17. The method of claim 16 wherein the force is multiple forces, and the position of touch is multiple positions of touch.
18. The method of claim 17 wherein the force is multiple forces, the position of touch is a centroid, and the magnitude of the force is a resultant of the multiple forces.
19. The method of claim 17 wherein the detecting of the partial forces is achieved by force sensors.
20. The method of claim 17 wherein the detecting of the partial forces is achieved by tracking the movement of the plurality of surfaces due to the force.
Type: Application
Filed: Jan 31, 2014
Publication Date: Jul 17, 2014
Applicant: (Newark, CA)
Inventor: Cherif Atia Algreatly (Palo Alto, CA)
Application Number: 14/169,822